The present invention relates to a process for the preparation of liquid fuels and the resulting fuel and, more particularly, a process that allows a high sulfur and nitrogen containing fuel to be converted into energy by combustion with a substantial reduction in sulfur oxide emissions and nitrogen oxide emissions.
Low gravity, viscous hydrocarbons found in Canada, The Soviet Union, United States, China and Venezuela are normally liquid with viscosities ranging from 10,000 to 200,000 CP and API gravities of less than 12. These hydrocarbons are currently produced either by mechanical pumping, steam injection or by mining techniques. Wide-spread use of these materials as fuels is precluded for a number of reasons which include difficulty in production, transportation and handling of the material and, more importantly, unfavorable combustion characteristics including high sulfur oxide emissions and unburned solids. To date, there are two commercial processes practiced by power plants to reduce sulfur oxide emissions. The first process is furnace limestone injection wherein limestone injected into the furnace reacts with the sulfur oxides to form solid sulfate particles which are removed from the flue gas by conventional particulate control devices. The cost for burning a typical high sulfur fuel by the limestone injection method is between two to three dollars per barrel and the amount of sulfur oxides removed by the methods is in the neighborhood of 50%. A more effective process for removing sulfur oxides from power plants comprises flue gas desulfurization wherein CaO+H.sub.2 O are mixed with the flue gases from the furnace. In this process 90% of the sulfur oxides are removed; however the cost for burning a barrel of fuel using the process is between four and five Dollars per barrel. Because of the foregoing, the high sulfur content, viscous hydrocarbons have not been successfully used on a commercial basis as fuels due to the high costs associated with their burning.
It is well known in the prior art to form oil in water emulsions for use as a combustible fuel. See for example U.S. Pat. Nos. 4,114,015; 4,378,230 and 4,618,348. In addition to the foregoing, the prior art teaches that oil in water emulsions formed from low gravity, viscous hydrocarbons can likewise be successfully combusted as a fuel. See for example British Patent Specification No. 974,042 and U.S. Pat. No. 4,618,348. The assignee of the instant application has discovered that sulfur-oxide emissions can be controlled when burning viscous high sulfur containing hydrocarbon in water emulsions by the addition of sulfur capturing additives to the emulsion composition. See U.S. Application Ser. Nos. 875,450 and 014,871.
Naturally, it would be highly desirable to develop a process for the preparation of liquid fuels and a resultant liquid fuel which, upon combustion, has a substantial reduction in sulfur oxide and nitrogen oxide emissions.
Accordingly, it is the principal object of the present invention to provide an additive for addition to a hydrocarbon fuel which, upon combustion of the fuel, acts as a sulfur and nitrogen capturing agent so as to substantially reduce the formation and emission of sulfur and nitrogen oxides.
It is a particular object of the present invention to provide a process as set forth above which is useful for hydrocarbon in water emulsions to be burned as fuels.
Further objects and advantages of the present invention will appear hereinbelow.